基于SBAS-InSAR技术监测廊坊市地面沉降

Study on surface deformation of Langfang based on SBAS-InSAR

地面沉降是廊坊市范围内的缓变地质灾害,为了分析该地区地表沉降特征,采用SBAS-InSAR时序分析方法,分别对Sentinel-1卫星2017年1月至2020年12月升、降两轨数据进行处理,得到雷达视线向形变,并进行融合分解得到垂直沉降和水平形变。结果表明,研究区内最大沉降速率达到100.2 mm/a,其间包含天津武清-廊坊霸州和廊坊固安县-保定雄县2个明显沉降漏斗。其中,廊坊固安县-保定雄县工业区由于受2020年南水北调工程的影响,地下水得到充分补给,地面沉降趋缓。受降雨影响,地表形变存在季节性波动。此外由于出台了地下水限采、禁采等措施,深层地下水位开采得到了有效控制,水位下降幅度减缓,2017-2020年累积沉降量呈现逐年递减趋势。

Land subsidence is a slowly changing geological disaster in Langfang City.We processed ascending and descending SAR data from Sentinel-1 satellite between January 2017 and December 2020,using SBAS-InSAR time series analysis method to obtain the radar line-of-sight(LOS)deformation.We combined the LOS displacements from ascending and descending data to decompose the vertical and horizontal components of deformation.The results show that the maximum subsidence rate in the study area reaches 100.2 mm/a,which exists two obvious subsidence areas:Tianjin-Wuqing-Langfang-Bazhou region and Langfang-Gu'an-Baoding-Xiongxian region.Among them,due to the impact of the South to North Water Transfer Project,groundwater in Langfang-Gu'an-Baoding-Xiongxian Industrial Zone has been recharged and the land subsidence has slowed down.Due to the impact of seasonal rainfall,there are seasonal fluctuations inthe displacement time series,which has a high correlation with the seasonal variations of rainfall.In addition,due to groundwater control practices such as groundwater extraction restriction and prohibition,the overexploitation of groundwater has been effectively controlled,and the decline of water level has slowed down.The cumulative subsidence iN_(2)017—2020 is decreasing year by year,mainly due to vertical settlement.